Lid opening/closing system of an airtight container

ABSTRACT

A curtain nozzle is located above an opening portion ( 10 ) in a FIMS. A gas curtain formed of inert gas for closing the opening portion is formed. A cover is so provided as to cover a part of the curtain nozzle so as to prevent peripheral gas around an opening of the curtain nozzle from being involved in the gas curtain of the inert gas emitted from the curtain nozzle.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a so-called front-opening interfacemechanical standard (FIMS) system used when wafers held in a transfercontainer which is called a pod are transferred among semiconductorprocessing apparatuses in a semiconductor manufacture process or thelike. To be more specific, the present invention relates to a FIMSsystem which has a purging mechanism for cleaning an inside of the podand in which the pod serving as an airtight container for containing thewafers, which is called a front-opening unified pod (FOUP), is placedand the wafers are put in and taken out from the pod for transfer of thewafer by opening/closing a lid of the pod, i.e., a lid opening/closingsystem.

2. Related Background Art

Up to now, a semiconductor manufacture process has been conducted in aso-called clean room in which semiconductor wafers are treated with highcleanliness maintained therein. However, in order to cope with anincrease in wafer size and reduce a cost required for maintenance of theclean room, a method of maintaining only the inside of a processingapparatus, the pod (wafer container), and a mini-environment forsubstrate transfer from the pod to the processing apparatus in a highlyclean state is employed in recent years.

The pod includes a main body portion having a substantially box-likeshape and a lid. The main body portion includes a rack capable ofholding a plurality of wafers therein in a state where the wafers areseparated from one another in parallel and an opening which is formed ona surface of the main body portion and is used for putting in/taking outwafers. The opening is closed with the lid. A pod in which the openingis located not on the bottom or top surface but on a side surfacethereof (in front of the mini-environment) is generically called afront-opening unified pod (FOUP). The present invention is mainlyintended for a structure using the FOUP.

The above-mentioned mini-environment includes a first opening opposed tothe opening of the pod, a door for closing the first opening, a secondopening provided on a semiconductor processing apparatus side, and atransfer robot that moves from the first opening to the inside of thepod to hold the wafer and passes through the second opening to transferthe wafer to the semiconductor processing apparatus side. A structurefor forming the mini-environment includes a mount base for supportingthe pod so that the opening of the pod is opposed to the front surfaceof the door.

A positioning pin inserted into a positioning hole provided on a bottomsurface of the pod to regulate a mount position of the pod and a clampunit engaged with a portion to be clamped which is provided on thebottom surface of the pod to fix the pod onto the mount base are locatedon an upper surface of the mount base. The mount base is normallymovable back and forth with respect to a door direction by apredetermined distance. When the wafers in the pod are to be transferredto the processing apparatus, the pod is moved in a state where the podis mounted on the mount base until the lid of the pod comes in contactwith the door. After that contact, the lid is removed from the openingof the pod by the door. With the operations described above, the insideof the pod is communicated with the inside of the processing apparatusthrough the mini-environment. Subsequently, wafer transfer operation isrepeated. A system including the mount base, the door, the firstopening, a door opening/closing mechanism, a wall which is a part of themini-environment including the first opening, and the like is generallycalled a front-opening interface mechanical standard (FIMS) system.

In ordinary cases, the inside of the pod with a wafer or the like loadedtherein is filled with dry nitrogen or the like which is controlled tobe highly clean to prevent the entry of contaminants, oxidizing gas, andthe like into the pod. However, when a wafer in the pod is introducedinto various kinds of processing apparatus to be subjected topredetermined processing, the inside of the pod and the inside of theprocessing apparatus are always kept communicating with each other. Afan and a filter are located above a chamber where the transfer robot islocated such that clean air with controlled particles and the like isintroduced into the chamber. However, when such the air enters the pod,there is a fear that the surface of the wafer may be oxidized by oxygenor moisture in the air.

As semiconductor devices get smaller and achieve higher performance,more attention is being paid to oxidation due to oxygen and the likethat enters the pod, which has conventionally not been such a bigproblem. Such oxidizing gas forms a very thin oxide film on the surfaceof the wafer or on various kinds of layers formed on the wafer. There isa possibility that, due to such the oxide film, desired characteristicsof the micro devices can not be secured. Measures against this includecontrol of the entry of gas without the partial pressure of oxygen andthe like therein being controlled from the outside of the pod into thepod. To be more specific, Japanese Patent Application Laid-open No.H11-145245 discloses a structure in which a region in a FIMS systemadjacent to a pod opening is provided with a supply nozzle and a suctionnozzle for gas to form an airflow curtain for substantially closing thepod opening. By forming the airflow curtain, the entry of external gasinto the pod is prevented.

In semiconductor manufacturing equipment, there are some cases where aprocess using gas which contaminates various kinds of wiring and thelike formed on the wafer such as an etching process is conducted inprocessing apparatus. A method of controlling the entry of the gas fromthe inside of the processing apparatus into the pod in this case isdisclosed in Japanese Patent Application Laid-open No. 2003-007799. Thismethod also forms an airflow curtain in front of a pod opening in a FIMSsystem using a fan to prevent the entry of the gas from the processingapparatus into the pod. This method is considered to be effective alsoin controlling inflow of oxygen into the pod as a matter of course.

SUMMARY OF THE INVENTION

However, when those methods were put to practical use, it was actuallyconfirmed that, immediately after the pod opening was opened, thepartial pressure of oxygen in the pod remarkably increased. Therefore,in order to meet the above-mentioned requirement, it is necessary tofurther improve those methods. The present invention is made in view ofthe above-mentioned situation, and an object of the present invention isto provide a lid opening/closing system of a pod as an airtightcontainer which makes it possible to control the partial pressure ofoxidizing gas such as oxygen in the pod at a predetermined low leveleven after the pod is opened.

To solve the above-mentioned problems, according to the presentinvention, there is provided a lid opening/closing system for insertingand removing an object to be contained by removing a lid from a storagecontainer to open an opening of the storage container which comprises asubstantially box-like main body capable of containing therein theobject to be contained and having the opening in one surface thereof,and a lid capable of being separated from the main body for closing theopening to form airtight space together with the main body. The lidopening/closing system comprises:

a mount base on which the storage container is mounted;

a substantially rectangular opening portion adjacent to the mount baseand facing the opening;

a door capable of holding the lid and capable of closing the openingportion, the door connecting the opening and the opening portion byopening the opening portion while holding the lid;

a curtain nozzle located outside a first side that is one of sides ofthe substantially rectangular opening portion on the side opposite tothe side where the mount base is located with respect to the openingportion and capable of ejecting inert gas substantially linearly towarda second side opposite to said first side; and

a cover which covers at least a part of said curtain nozzle so as toprevent gas around said curtain nozzle from being involved into theinert gas flow ejected from said curtain nozzle.

It should be noted that the above-mentioned cover defines a space arounda nozzle opening of the curtain nozzle that ejects the inert gas and thecover is open toward a direction of ejection of the inert gas by saidcurtain nozzle. Further, it is preferable that the above-mentioned coverfurther includes a pair of plate-like members which are located outsideof sides of the substantially rectangular opening portion other than thefirst and second sides thereof and which define a space of region of thegas flow ejected from the curtain nozzle in the side opposite to theside where the mount base is located with respect to the openingportion. Further, it is preferable that, the above-mentioned lidopening/closing system further includes an inert gas supply nozzle whichis located on inner side of the storage container than the curtainnozzle and which is adapted to eject inert gas toward the inside of thestorage container without having any component of gas flow directingtoward the inert gas flow ejected from said curtain nozzle. Further, itis preferable that the above-mentioned lid opening/closing systemfurther includes an inert gas supply nozzle composed of a pair oftubular nozzles which are located in parallel with sides of thesubstantially rectangular opening portion other than the first andsecond sides thereof and which have nozzle openings capable of ejectinginert gas directing toward the inside of the storage container.

According to the present invention, a gas curtain formed by inert gasflow is formed adjacent to a pod opening so as to close the opening, andinert gas is supplied to the inside of the pod. The supply of inert gasto the inside of the pod is carried out in a predetermined direction soas not to affect the gas curtain. To be more specific, the gas curtaincontrols the entry of gas from the outside of the pod into the pod, and,at the same time, inert gas is supplied to the inside of the pod, tomaintain the concentration of inert gas in the pod at a constant level.By combining those effects, even when the pod is open, the partialpressure of oxidizing gas in the pod is always maintained at apredetermined low level. Further, by combining those effects, comparedwith a case where the entry of oxidizing gas into a pod is prevented bysimply supplying inert gas to the inside of the pod and thus a largeamount of inert gas is necessary, comparable or better effect ofmaintaining the partial pressure of oxidizing gas at a low level can beobtained with an extremely small amount of inert gas.

Further, according to the present invention, the concentration of inertgas in the inert gas flow which forms the gas curtain itself can bemaintained at a high level. For example, it is known that, when gas isejected from a nozzle, the gas involves other gas existing close to anozzle opening and the gas mixture forms gas flow. To be more specific,because the gas forming the gas curtain involves other gas existingclose to the nozzle, the concentration of inert gas forming the gascurtain decreases, and there is a fear that oxidizing gas is suppliedfrom the gas curtain to the inside of the pod. According to the presentinvention, the nozzle opening is covered with the nozzle cover such thatgas existing close to the nozzle opening contains a high concentrationof inert gas. Therefore, even if such inert gas is involved, oxidizinggas is not involved in the gas curtain, and the entry of oxidizing gasinto the pod can be effectively controlled.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic structural view of a lid opening/closing system,in other words, a load port, a pod, a lid of the pod, and a part of anopener according to a first embodiment mode of the present inventionshown in a state of vertical section;

FIG. 1B is a view of a load port opening portion 10 shown in FIG. 1Aseen from a direction of the arrow 1B.

FIG. 1C is an enlarged view of a region surrounded by a dotted line 1Cshown in FIG. 1A of a curtain nozzle 12 and its adjacent structure.

FIG. 2 illustrates a modification of the lid opening/closing systemaccording to the first embodiment.

FIG. 3 is an enlarged view of a main portion of a lid opening/closingsystem according to a second embodiment of the present invention.

FIG. 4 is an enlarged view of a main portion of a lid opening/closingsystem according to a third embodiment of the present invention.

FIG. 5 is a side view illustrating a schematic structure of ordinarysemiconductor wafer processing apparatus as a whole to which the presentinvention is applied.

FIG. 6A is an enlarged side view illustrating a schematic structure of aconventional opener and an associated structure thereof in the apparatusshown in FIG. 5.

FIG. 6B illustrates a schematic structure of the structure shown in FIG.6A seen from the transfer chamber side.

FIG. 7 is a side view illustrating a schematic structure of an openerand the like in a state ready for purging to illustrate purge operation.

FIG. 8A is a sectional view illustrating a schematic structure of partof a lid opening/closing system, that is, a load port, a pod, a lid forthe pod, and an opener, according to a further embodiment of the presentinvention in a state of the vertical section.

FIG. 8B illustrates a load port opening portion 10 shown in FIG. 8A seenfrom a direction of the arrow 8B.

FIG. 8C illustrates a pod 2, a load port opening portion 10, and theirsurrounding structure shown in FIG. 8A seen from a direction of thearrow 8C.

FIG. 9A is a sectional view illustrating a schematic structure of partof a lid opening/closing system, that is, a load port, a pod, a lid forthe pod, and an opener, according to a further embodiment mode of thepresent invention in a state opf the vertical section.

FIG. 9B illustrates a load port opening portion 10 shown in FIG. 9A seenfrom a direction of the arrow 9B.

FIG. 9C illustrates a pod 2, a load port opening portion 10, and theirsurrounding structure shown in FIG. 9A seen from a direction of thearrow FIG. 10A is a sectional view illustrating a schematic structure ofpart of a lid opening/closing system, that is, a load port, a pod, a lidfor the pod, and an opener, according to a further embodiment mode ofthe present invention in a state of the vertical section.

FIG. 10B illustrates a load port opening portion 10 shown in FIG. 10Aseen from a direction of the arrow 10B.

FIG. 10C illustrates a pod 2, a load port opening portion 10, and theirsurrounding structure shown in FIG. 10A seen from a direction of thearrow 10C.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, embodiments of the present invention will be described withreference to the drawings. FIG. 1 is a schematic structural view of amain part of a lid opening/closing system (FIMS, hereinafter referred toas a load port) according to a first embodiment of the presentinvention, that is a side-view cross section of a pod and the main partof the load port which holds the pod with a lid thereof in an openstate. Note that the pod inherently includes various elements such as arack for supporting wafers and a seal member located between the lid ofthe pod and the pod. Further, various elements are attached to a doorand a base for supporting the pod. However, those members are notdirectly associated with the present invention, so the detailedillustration and description thereof will be omitted. It should be notedthat in the present invention a wafer 1 described below corresponds toan object to be contained, a pod 2 corresponds to a storage container, amain body portion 2 a corresponds to a main body defined to besubstantially in the shape of a box because its basic shape is a box,and an opening 2 b of the pod 2 corresponds to an opening defined to besubstantially in the shape of a rectangular because its basic shape is arectangular or square. A base 53 described below corresponds to a mountbase on which the storage container is mounted.

In FIG. 1A, inside a main body portion 2 a of the pod 2 there is a spacefor storing wafers 1, each of which is an object to be processed. Themain body portion 2 a has a box shape and includes an opening providedin one of surfaces constituting the side surfaces of the main body. Thepod 2 includes a lid 4 for closing the opening 2 b of the main bodyportion 2 a. The main body portion 2 a includes therein a rack (notshown) having a plurality of shelves for stacking the wafers 1 which arehorizontally held in a vertical direction. Each of the wafers 1 placedon the shelves is stored in the inside of the pod 2 at predeterminedintervals. The opening side of the pod 2 is adapted to face andcommunicate with a load port opening portion 10 which is provided on theload port portion side of a transfer chamber of the load port, whichwill be described below. The lid 4 is adapted to be held by a port door6 which normally closes the opening portion 10, and the lid 4 is causedto be moved by a drive mechanism (not shown) so that the opening of thepod 2 communicates with the transfer chamber 52 (shown as an openspace).

FIG. 1B illustrates a schematic structure of a load port opening portion10 seen from the direction of the arrow 1B of FIG. 1A. FIG. 1C is anenlarged view of a region surrounded by a dotted line indicated by 1Cshown in FIG. 1A. A curtain nozzle 12 is attached to an inner wall of atransfer chamber 52 above the load port opening portion 10. The curtainnozzle 12 has a nozzle main body 12 a, a first nozzle opening 12 b, anda second nozzle opening 12 c. As illustrated in FIG. 1B, the nozzle mainbody 12 a is formed of substantially a hollow pipe-like member whichextends in one direction (the direction perpendicular to the plane ofFIGS. 1A and 1C) and which has a length longer than the width of theload port opening portion 10. The inside of the hollow nozzle main body12 a is connected to a substantially pipe-like gas introduction path 13for introducing inert gas or the like from an outside region to theinside. One end of the gas introduction path 13 is, as illustrated inthe figure, connected to the nozzle main body 12 a, while the other endof the gas introduction path 13 is connected to an inert gasintroduction system (not shown). The inert gas introduction system cansupply inert gas of a predetermined flow rate from a gas supply under apredetermined pressure to the gas introduction path 13.

A first nozzle opening 12 b for forming inert gas flow in a directionparallel to an opening surface of the pod opening 2 b is formed in alower region of the nozzle main body 12 a. The first nozzle opening 12 bis a slit-like opening which extends in the direction in which thenozzle main body 12 a extends, and has a length longer than the width ofthe load port opening portion 10. Therefore, as illustrated in FIG. 1B,the inert gas flow ejected from the first nozzle opening 12 b forms agas curtain 14 which covers the whole load port opening portion 10. Thepressure and amount of the inert gas which is supplied from a gas supplysystem (not shown) through the gas introduction path 13 to the nozzlemain body 12 a are adjusted so as to be adequate for forming the gascurtain 14 which sufficiently closes the load port opening portion 10.

The nozzle main body 12 a further has the second nozzle opening 12 cformed therein. The second nozzle opening 12 c is formed in a lowerregion of the nozzle main body 12 a such an angle that the direction ofthe inert gas flow ejected from the second opening 12 c is directedtoward the inside of the pod through the load port opening portion 10and the pod opening. In other words, the second nozzle opening 12 c isformed such that the opening is directed toward an end portion of thewafer 1 contained in the pod 2 on the side of the pod opening 2 b.Therefore, the inert gas flow ejected from the second nozzle opening 12c is ejected toward inner space of the pod 2. In this way, a state underpositive pressure is formed in the pod 2 which is substantiallyspatially closed by the gas curtain 14 with respect to the outside ofthe pod space.

By a synergistic effect of the first nozzle opening 12 b and the secondnozzle opening 12 c described above, that is, by a synergistic effect ofpreventing by the gas curtain 14 the entry of external air or gas intothe pod and of preventing by making a pressure of inside of the podpositive the entry of external air or gas into the pod, the entry ofoxidizing gas into the pod can be effectively suppressed. It should benoted that, although, in this embodiment, the respective nozzle openingsare formed so as to be slit-like, dot-like openings may be additionallyprovided on a predetermined line at predetermined intervals. Further,although, in this embodiment, the first nozzle opening 12 b and thesecond nozzle opening 12 c are formed in the single nozzle main body 12a, taking into consideration the pressure and flow rate of inert gas tobe supplied, they may be formed in main body portions, respectively,which are independent of and separated from each other. Further, in thiscase, a plurality of nozzle openings may be provided in the nozzle mainbody for supplying inert gas to the inside of the pod such that theplurality of nozzle openings are generally directed toward the inside ofthe pod but specific directions of the nozzle openings may be differentfrom one another. Alternatively, the nozzle main body may be rotatableabout an axis along which the nozzle main body extends, so that inertgas can be directed from the nozzle opening via all the region of thepod opening into the inside of the pod.

It should be noted that, in this embodiment, there is a matter to whichattention should be paid when inert gas is supplied to the inside of thepod. To be more specific, it is indispensable that the direction ofsupply of inert gas is set so as not to have a component of gas flowdirecting toward the inert gas flow forming the gas curtain 14. The gascurtain is formed by mere gas flow. If the direction of supply of othergas has a component opposed to that flow, there is a fear that formationof the gas curtain may be hindered, airflow may be disturbed, and theentry of external gas into the pod may happen. For example, a structurein which so-called purge gas is supplied from a lower surface of the podto the inside of the pod is known. When the gas curtain according tothis embodiment is directly applied to the structure without anymodification, the direction of ejection of the purge gas has a componentopposed to the gas curtain. Therefore, it is necessary that at least thecomponent opposed to the gas curtain is substantially removed from thedirection of ejection of the purge gas. For example, by locating a purgegas outlet far from the pod opening toward the back of the pod, almostall the gas ejected from the outlet strikes a wafer immediately aboveand most of the gas flow is in the direction of planes in which thewafers extend. If the purge gas outlet is located in this way, the gascurtain can be suitably formed.

As a modification of this embodiment, a case where the second nozzleopening is located as an inert gas supply system which is a separatesystem is now described. FIG. 2 shows an enlarged view of a gas supplynozzle according to this embodiment in the same view as FIG. 1C. In aFIMS system, a so-called mapping sensor is located for deciding whichshelf in the pod has a wafer. The mapping sensor is formed of, forexample, a pair of sensors for emitting light and receiving lightlocated in parallel with the planes in which the wafers extend. Inactual detecting operation, these sensors are adapted to move so as tosandwich wafers therebetween so that presence or absence of a wafer isdetected by detecting whether light from a sensor is blocked by a waferor not. To be more specific, the sensors for emitting light andreceiving light are adapted to be introduced into the pod and are drivenin a direction of arrangement of the wafers. By attaching to thesesensors a nozzle 16 for supplying inert gas, inert gas can be suppliedto the inside of the pod.

However, when the gas curtain 14 is formed in a state in which thesensors are positioned in an area where a wafer exists, there is apossibility that the gas curtain 14 is blocked by the mapping sensor 15.In this case, because airflow forming the gas curtain 14 is disturbed,there is a possibility that external gas which fundamentally should notenter the pod might be mixed into the pod due to the disturbance of theairflow of the gas curtain. Therefore, in the structure, it ispreferable to form the gas curtain 14 in such configuration where, evenif the gas curtain 14 strikes the mapping sensor 15 and airflow isdisturbed, there is little adverse influence, that is, in a state wherethe respective sensors of the mapping sensor 15 are positioned at thelowermost end position of the pod. With the structure, inert gassupplied from the mapping sensor 15 side has little influence on the gascurtain 14, and, the influence of the existence of the mapping sensoritself on the gas curtain can be made as small as possible. Therefore,the above-mentioned effect of shielding the space with the gas curtainand effect of blocking, by supplying inert gas, the entry of externalgas can be preferably obtained.

Next, a further embodiment of the present invention is described. Itshould be noted that like reference numerals are used to designatestructural elements of this embodiment which exhibit like or identicalfunction, operation and effect to those of structural elements of theabove-mentioned embodiment. FIG. 8A illustrates a lid opening/closingdevice according to this embodiment in the same view as FIG. 1A. FIG. 8Billustrates a schematic structure of the load port opening portion 10 inthe device seen from the direction of the arrow 8B in FIG. 8A. FIG. 8Cillustrates a wafer and a plane in which the wafer extends, seen fromthe direction of the arrow 8C in FIG. 8A. In this embodiment also, thecurtain nozzle 12 for forming the gas curtain 14 and the nozzle forforming inert gas flow toward the inside of the pod are separatelyprovided, that is, the inert gas supply system having the second nozzleopening is provided separately from the gas curtain nozzle 12. In thisembodiment, as a structure having the second nozzle opening, a pair ofpurge nozzles 21 are provided.

The purge nozzles 21 have tubular purge nozzle main bodies 21 aextending in one direction and are connected to a purge gas supplysystem (not shown). The purge nozzle main bodies 21 a are located in apair adjacent to the outside of the load port opening portion 10 on bothsides thereof on the side opposite to the side of the mount base wherethe pod 2 is mounted with respect to the load port opening portion 10 soas to extend in parallel with the two sides of the opening portion 10. Aplurality of purge nozzle openings 21 b are provided in the purge nozzlemain bodies 21 a at predetermined intervals in the direction in whichthe purge nozzle main bodies 21 a extend such that the intervals equalto intervals at which the wafers 1 are positioned in the pod 2 and suchthat the purge nozzle openings 21 b are aligned to intervals between therespective wafers 1. Further, the purge nozzle openings 21 b are soformed as to be directed toward the center of the wafers 1.

The present embodiment includes major design modification on that twoinert gas supply systems, one of which is for the curtain nozzle 12 andthe other of which is for the purge nozzles 21 are required and theplurality of tubular members have to be located around the load portopening portion 10. However, this embodiment makes it possible to obtainthe effect of the gas curtain, and at the same time, purge gas can besupplied evenly to surfaces of the respective wafers 1. Further, inertgas can be supplied to the whole region inside the pod 2 with the leastresistance and without disturbing gas flow when the inert gas issupplied. Therefore, when atmosphere enters the pod 2 by opening andclosing the lid, further entry of atmosphere into the pod 2 can besuppressed by the gas curtain while the partial pressure of atmosphere(oxygen) in the pod can be promptly and effectively decreased by inertpurge gas.

It should be noted that, in this embodiment, tubular members located inparallel with the arrangement direction of the wafers in the pod 2, thatis, in parallel with two sides other than one side where the curtainnozzle 12 is located and a side opposed to the one side of the load portopening portion 10 are used as the purge nozzles 21. Further, theplurality of nozzle openings in the purge nozzles 21 are provided atpredetermined intervals in the direction in which the tubular membersextend and eject inert gas toward predetermined directions,respectively. However, location of the nozzle openings is not limitedthereto, and, as far as substantially linear inert gas flow can beformed along a predetermined direction such as a direction in parallelwith the sides, the location and shape of the nozzle openings and theshape of the purge nozzles are not limited to the ones described in thisembodiment.

Next, a main portion of a lid opening/closing device according to thesecond embodiment of the present invention is described in the followingwith reference to FIG. 3 illustrating a gas curtain nozzle in the sameview as FIG. 1C. It should be noted that, with regard to a structurewhich exhibit substantially like function, operation and effect to thoseof the structure illustrated in FIG. 1C, like reference numerals areused in the following description. Further, because the curtain nozzle12 in this embodiment has a structure similar to that of the curtainnozzle 12 described in the first embodiment except that it does not havethe second nozzle opening 12 c, the description thereof is omitted here.In this embodiment, the curtain nozzle 12 is covered with a nozzle cover18 so formed as to cover the nozzle main body 12 a. The nozzle cover 18has inner space 18 a which can accommodate the curtain nozzle 12 and isformed of a member forming an inner shape substantially similar to thecurtain nozzle 12.

The nozzle cover 18 further has a cover opening 18 b provided in itslower region. The curtain nozzle 12 is located in the inner space 18 aof the nozzle cover 18, and the first nozzle opening 12 b and the coveropening 18 b are located so as to be aligned with each other with regardto the direction of formation of the gas curtain 14. Here, thepositional relationship between the nozzle cover 18 and the curtainnozzle 12 is set such that the first nozzle opening 12 b is contained inthe inner space 18 a of the nozzle cover 18.

Further, in this embodiment, a communication opening 13 a whichcommunicates with the inner space 18 a of the nozzle cover 18 isprovided in the gas introduction path 13. By providing the communicationopening 13 a, this embodiment makes it possible to introduce inert gasinto the inside of the nozzle cover 18 and into the curtain nozzle 12through a single gas introduction system. It should be noted thatejection of inert gas from the inner space 18 a is basically notnecessary, and all what is necessary is that space around the firstnozzle opening 12 b is filled with inert gas. Therefore, the amount ofinert gas which is made to flow from the communication opening 13 a intothe inner space 18 a is sufficient if the inert gas fills the spacecovered with the nozzle cover 18.

It should be noted that, in this embodiment, the inner surface of a wallwhere the load port opening portion 10 is formed is used for forming apart of the nozzle cover 18, and the nozzle cover 18 is shown as amember formed of two surfaces, one of which is an upper surface portionand the other of which is a side surface portion connected to an end ofthe upper surface portion. However, the nozzle cover 18 may be formed asa substantially pipe-like member similarly to the curtain nozzle mainbody 12 a. Further, the nozzle cover 18 does not necessarily have tocover the whole curtain nozzle, and may cover only the space around thefirst nozzle opening 12 b. Still further, a path for supplying inert gasto the nozzle cover inner space 18 a may be provided separately from thegas introduction path 13. Therefore, the nozzle cover may have variousshapes and structures as far as the nozzle cover has a shape whichdefines some extent of space around the nozzle opening of the curtainnozzle so as to prevent gas around the nozzle opening of the curtainnozzle from being involved into the inert gas flow ejected from thenozzle opening of the curtain nozzle and which has an open regioncorresponding to the flow path of inert gas ejected from the nozzleopening of the curtain nozzle for forming the gas curtain.

In the lid opening/closing device according to this embodiment, thecurtain nozzle 12 for forming the gas curtain 14 is covered with thenozzle cover such that even gas existing close to the first nozzleopening 12 b contains a high concentration of inert gas. Therefore, evenif such inert gas is involved into the gas flow forming the gas curtain,oxidizing gas is not involved in the gas curtain 14, and the entry ofoxidizing gas into the pod can be effectively suppressed.

Next, a third embodiment of the present invention is described withreference to FIG. 4. FIG. 4 illustrates a main portion of a lidopening/closing device according to a third embodiment of the presentinvention in the same view as FIG. 1C or FIG. 3. An object of thisembodiment is to obtain two effects: to introduce inert gas into the podby the second nozzle opening 12 c used in the first embodiment; and toprevent oxidizing gas from being mixed into the gas curtain by thenozzle cover used in the second embodiment. To be more specific, thenozzle cover 18 illustrated in FIG. 3 is added to the curtain nozzle 12illustrated in FIG. 1C.

It should be noted that, because the specific structure of the curtainnozzle 12 and the specific structure of the nozzle cover 18 aresubstantially identical to those described above in the first and secondembodiments, detailed description of the respective structures isomitted here. In this embodiment, space around the second nozzle opening12 c is also covered with inert gas by using the nozzle cover 18. As aresult, high purity can be maintained also with regard to inert gasintroduced into the pod. Therefore, not only the above-mentioned effectof shielding the space with the gas curtain, effect of blocking, bysupplying inert gas, the entry of external gas, and effect of preventingthe mixing of oxidizing gas into the gas curtain can be obtained butalso high purity can be maintained with regard to gas introduced intothe pod.

It should be noted that, in this embodiment described above, the curtainnozzle is located above the opening portion. However, the embodiment ofthe present invention is not limited thereto. In view of efficientlytransferring an object to be contained such as a wafer, the pod openingand the opening portion are substantially in the shape of a rectangularwith its corners rounded. The curtain nozzle is located outside therectangular shape along one side of the rectangular. As far as inert gasis ejected toward a side opposed to said one side of the rectangular,the curtain nozzle may be located along whichever side of therectangular. The nozzle opening may be slit-like, dot-like, or acombination thereof as far as the inert gas flow is approximatelycontinuous in a section perpendicular to the direction of ejection andsubstantially forms a curtain, in other words, substantially linear.Further, it is preferable that inert gas is introduced into the podalways in a direction toward the inside of the pod (toward the center ofthe pod or toward a surface opposed to a surface having the openingformed therein). Therefore, it is preferable that the gas outlet islocated adjacent to a side along which the curtain nozzle is located andcloser to the inside of the pod than the curtain nozzle is.

Here, the nozzle cover in the embodiment described above is providedaround the curtain nozzle or the like with the intention of preventinginvolvement of environmental atmosphere in gas flow forming the gascurtain when the gas curtain is formed. However, the form of the coveris not limited to a nozzle cover, and, for example, a nozzle cover of atype which prevents diffusion of gas flow in the gas curtain may beprovided to prevent gas atmosphere from flowing toward the inside of thepod by the gas curtain. A structure with a nozzle cover of this type isdescribed in the following as a further embodiment of the presentinvention. It should be noted that, in explaining this embodiment, likereference numerals are used to designate structural elements of thisembodiment which exhibit like or identical function, operation andeffect to those of structural elements of the above-mentionedembodiment, and detailed description thereof is omitted. FIGS. 9A, 9B,and 9C illustrate a lid opening/closing device according to thisembodiment in the same view as FIGS. 8A, 8B, and 8C described above.

In this embodiment, in addition to the curtain nozzle 12 and the purgenozzles 21 illustrated in FIG. 8A and the like, a cover 23 is locatedaround the load port opening portion 10. The cover 23 is formed of threeplate-like members 23 a, 23 b, and 23 c having the same width. Theplate-like members protrude from a surface of the wall where the loadport opening portion 10 is formed on the side opposite to the side wherethe mount base is formed with respect to the load port opening portionso as to be perpendicular to the surface and so as to be in parallelwith the two sides and a top side of the load port opening portion 10.The plate-like members 23 a and 23 b along the two sides and theplate-like member 23 c along the top side are connected to one anotherat their ends intersecting one another to form a generally U-shapedmember which is open on a lower side of the load port opening portion10. The U-shaped member is located so as to protrude around the loadport opening portion 10, and the curtain nozzle 12 and the purge nozzles21 are housed inside the U-shape member.

According to this embodiment, the plate-like member 23 c along the topside decreases or prevents involvement of oxidizing gas in the gascurtain 14 supplied from the curtain nozzle 12. In other words, the mainobject of the plate-like member 23 c along the top side is to obtainthis effect, and may be in the shape of the nozzle cover of the secondembodiment. In order to obtain the effect with regard to the gascurtain, it is sufficient that the cover is configured to define acircumferential space around the region of the nozzle opening of thecurtain nozzle which ejects the inert gas to form the gas curtain flowso as to prevent any oxidizing gas from being involved in the gascurtain flow. The inert gas flow ordinarily diffuses with a largerextent as being farther from the curtain nozzle 12 where concentrationof the inert gas per unit volume reduces, and as a result the curtaineffect degrades. In this embodiment mode, the plate-like members 23 aand 23 b along the two sides prevent diffusion of inert gas in thedirection where these plate-like members exist, and the effect obtainedby the inert gas flow can be suitably maintained to a further downstreamside of the inert gas flow. Further, because the plate-like membersalong the two sides exist, involvement of oxidizing gas by inert gasflow when the purge nozzles 21 generates the gas flow can be decreasedor prevented.

It should be noted that, in this embodiment, the plate-like members 23 aand 23 b along the two sides are located so as to be in parallel withthe two sides of the load port opening portion 10. However, in view ofpreventing gas diffusion, the plate-like members may be slanted withrespect to the sides of the load port opening portion 10 such that thedistance from the plate-like members to the sides of the load portopening portion 10 decreases as the plate-like members approaches thebottom side of the load port opening portion. This gathers gas flowwhich flows between the plate-like members 23 a and 23 b along the sidestoward the center of the opening portion as the plate-like members 23 aand 23 b approach the bottom side of the opening portion, and thus, evenif part of the gas flow is gradually lost by diffusion, the same gasflow as that immediately after ejection can be maintained even at thebottom side of the opening portion. Further, the extending direction ofthe plate-like members 23 a and 23 b projected from the wall of the loadport along the sides may be slanted with respect to the normal to thewall of the load port or a plane on which the load port opening portionis formed such that the distance between the plate-like members becomesnarrower as being further away from the wall of the load port or theplane on which the opening portion is formed. The plate-like members 23a and 23 b along the sides are so inclined as to be directed toward theconvergent direction in the transfer chamber 52 (see FIG. 1), so thatgas flow which is about to diffuse can be concentrated to the placewhere the opening portion is formed, and thus, the gas flow can bemaintained as even flow over the whole region of the opening portion.Those slants are not always required to be provided over the wholeregion of the plate-like members, and may be provided over apredetermined portion. In this case, it is more preferable to providethe slants especially on a downstream side of the gas flow in the gascurtain where decrease in the concentration of inert gas is a concern.

As a further modification of this embodiment, another plate-like membersmay be additionally provided, which protrudes from each of theplate-like members at its end different from the end where theplate-like member is joined to the surface where the opening portion isformed and which is in parallel with the surface where the openingportion is formed, so as to protrude inwardly thereby forming acanopy-like U-shape. The present embodiment is illustrated in FIGS. 10A,10B, and 10C in the same way as in FIGS. 9A, 9B, and 9C. In thisembodiment, plate-like canopies 25 a and 25 b are fixed to the end ofthe plate-like members 23 a and 23 b on the sides, respectively. Becauseof the canopies, diffusion of inert gas in the gas curtain can be moresuitably suppressed, and the gas flow can be held flowing in a regionsurrounded by the plate-like members. It should be noted that the widthbetween the canopies 25 a and 25 b is set so as not to reduce the sizeof the load port opening portion 10. Further, the canopies may be fixedto the plate-like members 23 a and 23 b which are slanted with respectto the sides of the load port opening portion 10 as mentioned above.Further, the canopy may be provided with respect to the plate-likemember 23 c on the top side. To be more specific, the plate-like memberson the sides may be slanted on a downstream side of the gas curtain froma predetermined position of the load port opening portion 10 such thatthe distance between the plate-like members on the sides decreasestoward the downstream side of the gas curtain. Further, a canopy may beadded also to the plate-like member 23 c on the top side. Even if partof the gas flow is gradually lost, the same gas flow as that immediatelyafter ejection can be maintained even at the bottom side of the openingportion.

Next, a FIMS system as a lid opening/closing system which implements thepresent invention and semiconductor wafer processing apparatus using thesystem are described. It should be noted that, in this embodiment, acase where the curtain nozzle 12 described in the first embodiment isused is described first. FIG. 5 illustrates a schematic structure of asemiconductor wafer processing apparatus 50 which conforms to aso-called mini-environment system. The semiconductor wafer processingapparatus 50 is mainly formed of a load port portion (a FIMS system, alid opening/closing device) 51, the transfer chamber 52, and aprocessing chamber 59. A partition 55 a and a cover 58 a on the side ofthe load port and a partition 55 b and a cover 58 b on the side of theprocessing chamber are provided between the load port portion 51 and thetransfer chamber 52 and between the transfer chamber 52 and theprocessing chamber 59, respectively. In order to remove contaminants andmaintain high purity in the transfer chamber 52 of the semiconductorwafer processing apparatus 50, a fan (not shown) provided above thetransfer chamber 52 generates airflow from a top portion of the transferchamber 52 to a lower portion of the transfer chamber 52. This alwayslets out contaminants downward.

The pod 2 which is a storage container for storing silicon wafers or thelike (hereinafter merely referred to “wafers”) is mounted on the base 53located on the load port portion 51. As described earlier, the inside ofthe transfer chamber 52 is maintained to high cleanliness in order toprocess the wafers 1. Further, the transfer chamber 52 includes a robotarm 54. The wafers are transferred between the pod 2 and the processingchamber 59 by means of the robot arm 54. The processing chamber 59normally includes various mechanisms for performing processings, such asthin film formation and thin film processing on the surfaces of thewafers. However, the mechanisms are not directly related to the presentinvention, so the description will be omitted.

The pod 2 has a space for storing the wafers 1, each of which is theobject to be processed, in the inside thereof. The pod 2 includes thebox main body portion 2 a having the opening portion provided in one ofthe surfaces and the lid 4 for enclosing the opening portion. The mainbody portion 2 a includes the rack having the plurality of shelves forstacking the wafers 1 in one direction. Each of the wafers 1 placed onthe shelves are stored in the inside of the pod 2 at predeterminedintervals. In this embodiment, the direction in which the wafers 1 arestacked is set to the vertical direction. The opening portion 10 isprovided on the load port portion 51 side of the transfer chamber 52.When the pod 2 is to be located on the load port portion 51 such thatthe pod 2 is close to the opening portion 10, the opening portion 10 islocated to face the opening portion of the pod 2. The transfer chamber52 includes an opener 3 (described later) provided on the inner side inthe vicinity of the opening portion 10.

FIG. 6A is an enlarged side cross sectional view showing an opener 3 ina conventional apparatus and FIG. 6B is a font view showing the opener 3which is viewed from the transfer chamber 52 side. FIG. 7 is a schematicside cross sectional view showing a state where the lid 4 is removedfrom the pod 2 using the opener 3. The opener 3 includes the door 6 anda door arm 42. A fixing member 46 is installed on the door 6. The door 6is pivotably connected to one end of the door arm 42 through the fixingmember 46. The door arm 42 is supported at the other end thereof to atip end portion of a rod 37 which is a part of air-drive cylinder 31through a pivot axis 40 to be pivotable about the pivot axis 40.

A through hole is provided between the one end of the door arm 42 andthe other end of the door arm 42. A pin (not shown) extends through thethrough hole and a hole of a fixed member 39 fixed to a support member60 of a movable portion 56 for moving the opener 3 up and down, therebyforming a supporting point 41. Therefore, the door arm 42 is pivotableabout the supporting point 41 according to the extension and retractionof the rod 37 due to the drive of the cylinder 31. The support point 41of the door arm 42 is fixed to the support member 60 to which thevertically movable portion 56 is provided. The door 6 includes holdingports 11 a and 11 b and thus can hold the lid 4 of the pod 2 by vacuumcontact.

When the wafer 1 is processed by the above-mentioned structure, first,the pod is located on the base 53 so as to be adjacent to the transferchamber opening portion 10, and the lid 4 is held by the door 6. Itshould be noted that a mechanism-to-engage (not shown) is provided on asurface of the door 6 while a mechanism-to-be-engaged (not shown) isprovided on a surface of the lid 4. By actuating those mechanisms withthe surfaces of the lid 4 and of the door 6 in contact with each other,the lid 4 is held by the door 6. Here, when the rod of the cylinder 31is retracted, the door arm 42 moves away from the transfer chamberopening portion 10 with the supporting point 41 being the rotation axis.According to this action, the door 6 rotates together with the lid 4 toremove the lid 4 from the pod 2, as illustrated in FIG. 7. After that,the movable portion 56 is lowered to move the lid 4 to a predeterminedretreat position.

The curtain nozzle 12 according to the present invention is located in atop portion of the transfer chamber opening portion 10. After the lid 4is removed using the port door 6, the curtain nozzle 12 forms the gascurtain 14, and, at the same time, supplies inert gas to the inside ofthe pod. It is preferable that, in order to avoid a large change in theinternal pressure of the transfer chamber 52 and the like when clean gasis supplied, exhaust operation of various kinds such as suction exhaustof the transfer chamber be simultaneously carried out corresponding togas supply operation.

Further, in this embodiment, the description is in the context of FOUPand FIMS, but application of the present invention is not limitedthereto. As far as the container is a front-opening type container whichcontains a plurality of objects to be contained and is opened and closedwhen the objects to be contained are inserted into or removed from thecontainer in the system, the lid opening/closing device according to thepresent invention can be applied to maintain the partial pressure ofoxidizing atmosphere in the container at a low level. Further, when thegas which fills the container is not inert gas but predetermined gashaving desired characteristics, the lid opening/closing system accordingto the present invention can be used to maintain the partial pressure ofthe predetermined gas in the container at a high level.

According to the present invention, the effect of shielding the spacewith the gas curtain, the effect of suppressing, by supplying inert gas,the entry of external gas, and the effect of preventing oxidizing gasfrom being mixed into the gas curtain can be obtained, and further, highpurity can be maintained with regard to gas introduced into the pod.Further, the present invention can be implemented only by adding to anexisting FIMS system a gas supply pipe and the like, which can be addedto a standardized system easily at low cost.

This application claims priority from Japanese Patent Applications No.2005-346083 filed on Nov. 30, 2005 and No. 2006-314202 filed on Nov. 21,2006, which are hereby incorporated by references herein.

1. A lid opening/closing system for inserting and removing an object tobe contained by removing a lid from a storage container to open anopening of the storage container, the storage container comprising asubstantially box-like main body capable of containing therein theobject to be contained and having the opening in one surface thereof,and a lid capable of being separated from the main body for closing theopening to form airtight space together with the main body, the lidopening/closing system comprising: a mount base on which the storagecontainer is mounted; a substantially rectangular opening portionadjacent to the mount base and facing the opening; a door capable ofholding the lid and capable of closing the opening portion, the doorconnecting the opening and the opening portion by opening the openingportion while holding the lid; a curtain nozzle located outside a firstside that is one of sides of the substantially rectangular openingportion on the side opposite to the side where the mount base is locatedwith respect to the opening portion and capable of ejecting inert gassubstantially linearly toward a second side opposite to said first side;and a cover which covers at least a part of said curtain nozzle so as toprevent gas around said curtain nozzle from being involved into theinert gas flow ejected from said curtain nozzle.
 2. A lidopening/closing system according to claim 1, wherein said cover definesa space around a nozzle opening of said curtain nozzle that ejects theinert gas and said cover is open toward a direction of ejection of theinert gas by said curtain nozzle.
 3. A lid opening/closing systemaccording to claim 1, wherein said cover further includes a pair ofplate-like members which are located outside of sides of thesubstantially rectangular opening portion other than said first andsecond sides thereof and which define a space of region of the gas flowejected from said curtain nozzle in the side opposite to the side wherethe mount base is located with respect to the opening portion.
 4. A lidopening/closing system according to claim 1, further comprising an inertgas supply nozzle which is located on inner side of the storagecontainer than the curtain nozzle and which is adapted to eject inertgas toward the inside of the storage container without having anycomponent of gas flow directing toward the inert gas flow ejected fromsaid curtain nozzle.
 5. A lid opening/closing system according to claim3, further comprising an inert gas supply nozzle composed of a pair oftubular nozzles which are located in parallel with sides of thesubstantially rectangular opening portion other than said first andsecond sides thereof and which have nozzle openings capable of ejectinginert gas directing toward the inside of the storage container.